I've read in a few articles about engine block water jackets being tapped for petcocks to make draining fluid easier than just yanking a plug.

I've never seen it discussed here, and it seems like it would make it easy to drain off a limited amount of coolant for head swaps, knock sensor replacements, coolant flushes, etc...

Is this a big no-no for a performance engine?
Would a petcock in a easy-access area be a generally good idea?

Has anyone had or know of problems with this idea? Would an aluminum radiator petcock be the petcock of choise? (from an electro-potential aspect)

Just looking for some discussion on this... seems like a good idea during a rebuild

 

i've relocated block's drain hole many times over years
due to using HardBlock and engines mostly in Dragsters

on my Dragster's engine block is drilled/tapped for #6 AN male fitting and steel braided lines run to rear of Dragster to Earl's aircraft style petcocks....where i dump block's water in Pits after a DragStrip pass

Every once in awhile some one comes to Dyno with Petcocks in Block..sure makes it easy to drain water out of engine when its time to take the Engine off the Dyno

 

When you drain the rad, you don't drain all the antifreeze from the system. Both sides of the block will still have coolent in them. There's plugs already in the bottom of the block to drain the coolent especially when you pull a head. You can easily pull the plug and install a petcock in those holes but sometimes they're behind the engine mounts and hard to get at.

My block is filled to the bottom of the freeze plugs. I drilled and tapped a 1/4" NPT hole at the front sides of both sides of my block and installed petcocks there so I can get at them easier. The holes are inline with the bottom of the freeze plug.